Answer:
- small: 5 yards
- large: 8 yards
Step-by-step explanation:
Using s and L to represent the amount of ribbon used for small barrettes and large barrettes, respectively, we have ...
12s +12L = 156
10s +11L = 138
Dividing the first equation by 12 gives ...
s +L = 13
Substituting s = 13-L into the second equation gives ...
10(13 -L) +11L = 138
130 +L = 138 . . . . . . . simplify
L = 8 . . . . . . . . . . subtract 130
s = 13 -8 = 5 . . . . find s
Rachel uses 5 yards for a small barrette, and 8 yards for a large barrette.